Wireless Access

Contributor I

VLAN Pooling Hash vs. Even

We have moved to even vlan pooling in efforts to stabilize the uneven distribution of IP's across the 4 /23 vlans we have in a pool.  What we're seeing is many clients are getting new IP's after deatuhs/ auths on the AP (i'm guessing devices going to sleep and waking up like mobile phones).


If we use even vlan pooling - and a device disconnects from an AP and connects back right away, it's back to Aruba using round-robin on what vlan the client will be place in, correct?  Only the HASH method contains a database of Mac -> Vlan? 


Any better way to keep client to vlan distribution in a pool more even?  


Currently on even pooling we have 2 vlans at 90% capacity and 2 vlans at 20% capacity.





Re: VLAN Pooling Hash vs. Even


Are you sharing these VLANs accross different controllers ?


Have you tried using the show ap vlan-usage to see the distribution accross VLANs on the controllers.





Thank you

Victor Fabian
Lead Mobility Architect @WEI
Guru Elite

Re: VLAN Pooling Hash vs. Even

"When a VLAN pool is shared across multiple controllers, each controller has its own snapshot of VLAN usage. This
info is not explicitly shared across the controllers. Each controller works independently to determine the VLAN
assignment based on its snapshot of VLAN usage. If a large number of users leave a controller and move to a different
controller, it can cause a temporary drop in usage in some VLANs. However, because each of the controllers is always
trying to keep the VLAN usage even, we will not have a completely starved VLAN."

| Tim Cappalli | Aruba Security | @timcappalli | timcappalli.me |

NOTE: Answers and views expressed by me on this forum are my own and not necessarily the position of Aruba or Hewlett Packard Enterprise.
Contributor I

Re: VLAN Pooling Hash vs. Even

That makes sense.  Thanks for the command and the explanation.


So if a client roams between ap's he should keep his IP throughout.

But if the nic disaccoiates for whatever reason and associates the controller continues it's calculation on what the next vlan should be based on vlan usage... correct?



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